Martha chose soapstone (named for its smooth, “soapy” touch) for all the countertops in her studio kitchen. Primarily composed of talc, soapstone is light gray when fresh from the quarry, but its surface oxidizes over time, deepening in color and developing an attractive patina — a process you can expedite by oiling the stone once a month for the first year after it is installed. Martha applies a refined mineral oil to the entire countertop with a soft, low-lint cotton rag. (If necessary, use a small paintbrush for hard-to-reach edges.) After each application, wipe off the excess oil with a clean rag.
Soapstone is softer and more malleable than marble or granite — it can be sawed and sanded like wood — so it is easy to repair nicks and chips in its surface. Simply sand the target spot with a small piece of 80-grade sandpaper, and apply oil to the repaired area. Although soft, soapstone is durable: The nonporous surface resists stains and burns and is impervious to acids, a quality that has made it a popular choice for countertops in laboratories and darkrooms.
Martha also requested a deep butler’s sink made of soapstone; because the stone retains heat better than materials such as steel or enamel, the dishwater stays hot longer — a quality that made soapstone a popular choice for sinks before the days of hot running water. When the studio sink is not being used, a custom-made plastic cover fits over it to maximize the counter space on the kitchen island.
Read more at Marthastewart.com: How to Cure Soapstone – Martha Stewart Home and Garden